What industry uses the Janka hardness ratings scale?

The Janka scale or Janka hardness rating scale is used in the flooring industry as a comprehensive chart of hardness ratings for a huge variety of wood species used for hardwood floors. It is generally used only as a guide. Red Oak, which has a Janka rating of 1290, is the industry benchmark for comparing the relative hardness of different wood species.

Basically, with the Janka scale ratings, a wood's relative hardness is determined when it measures the force required to drive a .444 inch steel ball into the wood until half the diameter of the ball is imbedded in the wood. The higher the number on the scale the harder the wood. This is one of the best measures of the ability of wood species to withstand denting and wear. It is also a good indicator of how hard a species is to saw or nail.

Specific results with the ratings have been stated in various ways (which can lead to confusion) especially when the actual units employed are often not attached as samples. Overall, the resulting rate measurement is always one of force. In the United States, the measurement is in pounds-force (lbf). In Sweden it is in kilograms-force (kgf), and in Australia, either in newtons (N) or kilonewtons (kN). Sometimes the results are treated as units, for example "660 Janka.